Installing new mast base.

if you mean the aluminum insert that goes in the bottom on the mast, then yes, just drill out the rivets and replace. not quite as easy as it sounds, i actually had to cut 3/16" off the bottom of the mast extrusion to gain new ground for better holes. my advice, silicon the mast base, stick it in and let it dry. then completely redrill all new holes for the rivets. if the holes in your mast are ok you may not have to do this, but i tried using the old holes and couldn't get the base to seat right.

I recently redid the connnection of my mast base. The two rivets were starting to tear loose. I drilled out the old rivets and drilled and tapped 4 new holes for 1/4-20 x 1/2 BHSCS. The only thing that concerned me was how thin the aluminum of the base was to tap into. I just made sure that I used loctite and didn't torque too much. Seems to be working just fine so far.

Forgive my ignorance, but what are 1/4-20 x 1/2 BHSCS?

Nick,

1/4" dia 20 threads per inch 1/2" long, stainless steel, button head socket cap screw. A lot of words for such a small thing.

A side issue to mast base replacements...

The likely way the mast base attachment rivet areas fail is during stepping. Be sure that your mast step link directs the base into the step casting properly. If the link allows the base to hit the step forward of the cup, you can leverage the base out of the mast. That rips either the mast extrusion or the base casting at the rivet locations. Another way to avoid this damage is to slow down the stepping process when the mast nears the upright position, pull back the the lower end of the mast to be sure that the base drops into the cup.